Hydrocarbon drilling and production operations demand a great quantity of information relating to parameters and conditions downhole. Such information may comprise characteristics of the earth formations traversed by the borehole, as well as characteristics of the various fluids within the earth formations traversed by the borehole. Systems for measuring conditions downhole, including the movement and location of the drilling assembly contemporaneously with the drilling of the well, have come to be known as “measurement-while-drilling” techniques, or “MWD”. Similar techniques, concentrating more on the measurement of formation parameters, have come to be known as “logging while drilling” techniques, or “LWD”. While distinctions between MWD and LWD may exist, the terms MWD and LWD often are used interchangeably. For purpose of this disclosure, the term MWD will be used with the understanding that this term encompasses both the collection of formation parameters and the collection of information relating to the movement and position of the drilling assembly. In other situations, the parameters and conditions downhole may be detected by wireline devices placed in the borehole after the drill string has been removed or “tripped”.
Many difficulties exist in performing MWD, such as limited space in which to perform testing and the conditions experienced downhole. For example, the temperature in deep hydrocarbon wells may reach or exceed 450 degrees Fahrenheit. Electronic devices designed and constructed for temperature ranges expected for surface applications may have severely reduced performance at expected downhole temperature, and in many cases are inoperable at expected downhole temperatures. The temperature operability problem is particularly pronounced for devices used to detect electromagnetic radiation, such as may be used in downhole spectroscopy.
Thus, any advance which overcomes difficulties relating to operation of devices at elevated temperature would provide a competitive advantage in the industry.